I have a laptop with Windows 8 and it's good enough for games, but I don't know if GTA IV will work ok - it's not such a new game. Any ideas?
you shouldn't have any problems installing the game.
However, there is one minor problem: GTA IV requires Games for Windows Live extension and it may cause some problems on Windows 8, since it has been updated and renamed by Microsoft when introducing that new system. If you have problems with that extension you will have to uninstall it completely from the system and then download the updated version called Games for Windows Marketplace Client that includes all the newest Games for Windows Live libraries you need for playing GTA IV. I hope it helps.